<?php

require_once 'HTMLPurifier/AttrDef/URI/IPv4.php';

/**
 * Validates an IPv6 address.
 * @author Feyd @ forums.devnetwork.net (public domain)
 * @note This function requires brackets to have been removed from address
 *	   in URI.
 */
class HTMLPurifier_AttrDef_URI_IPv6 extends HTMLPurifier_AttrDef_URI_IPv4
{
	
	function validate($aIP, $config, &$context) {
		
		if (!$this->ip4) $this->_loadRegex();
		
		$original = $aIP;
		
		$hex = '[0-9a-fA-F]';
		$blk = '(?:' . $hex . '{1,4})';
		$pre = '(?:/(?:12[0-8]|1[0-1][0-9]|[1-9][0-9]|[0-9]))';   // /0 - /128
		
		//	  prefix check
		if (strpos($aIP, '/') !== false)
		{
				if (preg_match('#' . $pre . '$#s', $aIP, $find))
				{
						$aIP = substr($aIP, 0, 0-strlen($find[0]));
						unset($find);
				}
				else
				{
						return false;
				}
		}
		
		//	  IPv4-compatiblity check	   
		if (preg_match('#(?<=:'.')' . $this->ip4 . '$#s', $aIP, $find))
		{
				$aIP = substr($aIP, 0, 0-strlen($find[0]));
				$ip = explode('.', $find[0]);
				$ip = array_map('dechex', $ip);
				$aIP .= $ip[0] . $ip[1] . ':' . $ip[2] . $ip[3];
				unset($find, $ip);
		}
		
		//	  compression check
		$aIP = explode('::', $aIP);
		$c = count($aIP);
		if ($c > 2)
		{
				return false;
		}
		elseif ($c == 2)
		{
				list($first, $second) = $aIP;
				$first = explode(':', $first);
				$second = explode(':', $second);
			   
				if (count($first) + count($second) > 8)
				{
						return false;
				}
			   
				while(count($first) < 8)
				{
						array_push($first, '0');
				}

				array_splice($first, 8 - count($second), 8, $second);
				$aIP = $first;
				unset($first,$second);
		}
		else
		{
				$aIP = explode(':', $aIP[0]);
		}
		$c = count($aIP);
		
		if ($c != 8)
		{
				return false;
		}
	   
		//	  All the pieces should be 16-bit hex strings. Are they?
		foreach ($aIP as $piece)
		{
				if (!preg_match('#^[0-9a-fA-F]{4}$#s', sprintf('%04s', $piece)))
				{
						return false;
				}
		}
		
		return $original;
		
	}
	
}

